Northstar Engines and System Technical Discussion Discussion, Northstar noise in Cadillac Engine Discussion; I have read and re-read all the info about the fact that Northstars have a tendency to knock/tap some. Just ...

Northstar noise

I have read and re-read all the info about the fact that Northstars have a tendency to knock/tap some. Just tonight I tried WOT to see if that would burn some carbon and ease the noise some. It does not seem to have done anything. The car runs great, and it is a great car.

When I bought the car in October of 05 it did not make any noises. Then early in December sometime it started to. I thought cold weather or oil needed changed which it did. I had it changed and since the weather from December in Iowa of single digits and below zero has been mild here in mid January. Still have the noise.

I love this car, but being a new Northstar owner just am worried somewhat.

Re: Northstar noise

Well that is what I thought, but what are we defining as cold??? I knew in Decemver with single and below 0 degree days, that is definately cold, but in the upper 30's and low 40's??? I would have thought it would not do it. I will try a couple more WOT's. I have fun doing it anyways... Just wish the TOP SPEED FUEL OFF would not come on at 112...

Re: Northstar noise

Cold as in, the engine is cold, not the air outside. Cold is anything less than 150 degrees F. (give or take)

Make sure when you do your WOTs that your engine is up to temperature. Cold oil is high pressure viscous oil that won't protect your engine as well as warm oil. Not to mention it's not good for it. For really stubborn cases of carbon knocking, you might want to check the top engine cleaner thread in tech tips.

Re: Northstar noise

I will do that, and yes the car was warm. It was up over 150 degrees. I did notice last night while I was waiting for my girlfriend to get out of work. I listened under the hood of the car and it seems that the noise is coming from the back driver side of the engine or that area.

Re: Northstar noise

I also have a noticable knock. It's not too too loud, but the wierd thing is that it appeared the just after, on the same day as, when I had cleaned the engine with the GM engine cleaner. (Don't remember the name?) I was worried whether or not I had broken something loose? Or maybe it does that now that it has a better breath? Anyone know how cleaning the engine could have done this?

Re: Northstar noise

Originally Posted by ELDOminator

I also have a noticable knock. It's not too too loud, but the wierd thing is that it appeared the just after, on the same day as, when I had cleaned the engine with the GM engine cleaner. (Don't remember the name?) I was worried whether or not I had broken something loose? Or maybe it does that now that it has a better breath? Anyone know how cleaning the engine could have done this?

Re: Northstar noise

I had the same knocking noise on my Northstar, I don't drive my car frequently and it was cold the day I went to start it, it started to knock. I was like, what the heck! I shut the car and restarted it and it kept on knocking. It was loud in the beginning but then it got less and less but it was still there. I saw that some other people had posted about the same thing and it was suggested to do some WOT'S, I did what was suggested and no more knock. Do more than one and you may get some results like I did.. Good luck!

Re: Northstar noise

Originally Posted by mtflight

Oh. Did you change the oil right afterwards?

I hadn't changed it right afterwards, no. But I did a little while afterwards and it did seem to help. I never read to change the oil just after cleaning it. I guess it seems obvious to me now and I will always change it afterwards.

Re: Northstar noise

Originally Posted by ELDOminator

I hadn't changed it right afterwards, no. But I did a little while afterwards and it did seem to help. I never read to change the oil just after cleaning it. I guess it seems obvious to me now and I will always change it afterwards.

The bulletin does not mention it, but eldorado1 did.

So how long did you leave the TEC in the engine? I want to do the procedure because I hear valve clatter with the hood open and it may help.

Re: Northstar noise

I let it sit for ... I wanna say 5? But maybe it was 15? One of those 5 numbers... It wasn't long because I asked myself, "can I put all this back together in XX amount of time?" So it was probably 5 minutes.